The present invention relates generally to the area of information processing and, specifically, to system and methods for storing information in one device, particularly a portable (e.g., hand-held) computing device, and transferring that information to another computing device.
With compact, portable computing devices becoming ever more popular because of advances in manufacturing and power consumption, there is an increasing desire to carry more and more personal information on such devices. Storage of increasing amounts of data on such devices is easily handled by increasing solid state storage capacity.
Because of form factor constraints, portable devices are often designed with minimal input capabilities, often making data entry cumbersome or even impossible. For this reason, portable computing devices are most effective as a component of a solution involving connectivity with larger, more input capable devices such as desktop computers, laptop computers and information servers.
The increase in data volume on portable devices, combined with the need to transfer data to and from other larger devices, presents a connectivity problem. In particular, connection speeds rarely match storage capacity and data size requirements. One method to assist data flow is data compression. Another, more effective method, which can be combined with compression, is to achieve minimal data transfer through "deltas" or differences between two data sets.
Typical file systems are designed for storage and retrieval of data, focusing on storing and retrieving large amounts of data on slow electro-mechanical devices. Such file systems typically store information in block chains represented in a specific storage area. The popular "FAT" storage system represents block chains in a designated area called the File Allocation Table. This mechanism is well suited for large capacity, mechanical storage devices because the allocation table, a table in constant use, can be cached in computer memory and accessed without typical mechanical penalties such as seek time and transfer time. This type of file system, however, is not suited for minimal data transfer. In particular, storage on a portable device is usually solid state (e.g., RAM or random-access memory), not mechanical. The issues with seek time and data transfer time are minimized--practically non-existent--with solid state storage technology. The issue of minimal data transfer remains, however.
What is needed is a file system structure designed for minimizing data transfer, rather than one designed for minimizing the access constraints of mechanical storage devices. The present invention fulfills this and other needs.